Head with supplemental module for backward and/or cross-platform compatibility

ABSTRACT

In one general embodiment, an apparatus includes at least one first module configured for writing and/or reading data to and from a magnetic medium in a first format and/or first generation and writing data to the magnetic medium in a second format and/or second generation that is different than the first format and first generation. The apparatus also includes a supplemental module coupled to the first module, the supplemental module being configured for reading a magnetic medium having data written in the second format and/or the second generation.

RELATED APPLICATIONS

This application is a continuation of copending U.S. patent applicationSer. No. 13/741,352, filed Jan. 14, 2013; which is herein incorporatedby reference.

BACKGROUND

The present invention relates to data storage systems, and moreparticularly, this invention relates to magnetic tape heads havingsupplemental modules for backward and/or cross-platform compatibility.

In magnetic storage systems, data is read from and written onto magneticrecording media utilizing magnetic transducers. Data is written on themagnetic recording media by moving a magnetic recording transducer to aposition over the media where the data is to be stored. The magneticrecording transducer then generates a magnetic field, which encodes thedata into the magnetic media. Data is read from the media by similarlypositioning the magnetic read transducer and then sensing the magneticfield of the magnetic media. Read and write operations may beindependently synchronized with the movement of the media to ensure thatthe data can be read from and written to the desired location on themedia.

An important and continuing goal in the data storage industry is that ofincreasing the density of data stored on a medium. For tape storagesystems, that goal has led to increasing the track and linear bitdensity on recording tape, and decreasing the thickness of the magnetictape medium. However, the development of small footprint, higherperformance tape drive systems has created various problems in thedesign of a tape head assembly for use in such systems.

In a tape drive system, magnetic tape is moved over the surface of thetape head at high speed. Usually the tape head is designed to minimizethe spacing between the head and the tape. The spacing between themagnetic head and the magnetic tape is crucial and so goals in thesesystems are to have the recording gaps of the transducers, which are thesource of the magnetic recording flux in near contact with the tape toeffect writing sharp transitions, and to have the read elements is innear contact with the tape to provide effective coupling of the magneticfield from the tape to the read elements.

BRIEF SUMMARY

An apparatus according to one embodiment includes at least one firstmodule configured for writing and/or reading data to and from a magneticmedium in a first format and/or first generation and writing data to themagnetic medium in a second format and/or second generation that isdifferent than the first format and first generation. The apparatus alsoincludes a supplemental module coupled to the first module, thesupplemental module being configured for reading a magnetic mediumhaving data written in the second format and/or the second generation.

A method according to one embodiment includes detecting a format inwhich data on a magnetic medium is written. A module configured forwriting and/or reading data to and from the magnetic medium in a firstformat is used when the format detected is the first format. Asupplemental module coupled to the module for reading data from themagnetic medium in a second format is used when the format detected isthe second format.

Any of these embodiments may be implemented in a magnetic data storagesystem such as a tape drive system, which may include a magnetic head, adrive mechanism for passing a magnetic medium (e.g., recording tape)over the magnetic head, and a controller electrically coupled to themagnetic head.

Other aspects and embodiments of the present invention will becomeapparent from the following detailed description, which, when taken inconjunction with the drawings, illustrate by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1A is a schematic diagram of a simplified tape drive systemaccording to one embodiment.

FIG. 1B is a schematic diagram of a tape cartridge according to oneembodiment.

FIG. 2 illustrates a side view of a flat-lapped, bi-directional,two-module magnetic tape head according to one embodiment.

FIG. 2A is a tape bearing surface view taken from Line 2A of FIG. 2.

FIG. 2B is a detailed view taken from Circle 2B of FIG. 2A.

FIG. 2C is a detailed view of a partial tape bearing surface of a pairof modules.

FIG. 3 is a partial tape bearing surface view of a magnetic head havinga write-read-write configuration.

FIG. 4 is a partial tape bearing surface view of a magnetic head havinga read-write-read configuration.

FIG. 5 is a side view of a magnetic tape head with three modules wherethe modules all generally lie along about parallel planes, and asupplemental module, according to one embodiment.

FIG. 6 is a side view of a magnetic tape head with three modules in atangent (angled) configuration, and multiple supplemental modules,according to one embodiment.

FIG. 7 is a side view of a magnetic tape head with three modules in anoverwrap configuration, and a supplemental module, according to oneembodiment.

FIG. 8 is a side view of a magnetic tape head with two modules, and asupplemental module, according to one embodiment.

FIG. 9 is a flowchart for a method according to one embodiment.

FIG. 10 is a flowchart for a method according to one embodiment.

DETAILED DESCRIPTION

The following description is made for the purpose of illustrating thegeneral principles of the present invention and is not meant to limitthe inventive concepts claimed herein. Further, particular featuresdescribed herein can be used in combination with other describedfeatures in each of the various possible combinations and permutations.

Unless otherwise specifically defined herein, all terms are to be giventheir broadest possible interpretation including meanings implied fromthe specification as well as meanings understood by those skilled in theart and/or as defined in dictionaries, treatises, etc.

It must also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an” and “the” include pluralreferents unless otherwise specified.

The following description discloses several preferred embodiments ofmagnetic storage systems, as well as operation and/or component partsthereof.

In one general embodiment, a magnetic head includes at least one firstmodule configured for writing and/or reading data to and from a tape ina first format and/or first generation and writing data to the tape in asecond format and/or second generation that is different than the firstformat and first generation; and a supplemental module coupled to thefirst module, the supplemental module being configured for reading atape having data written in the second format and/or the secondgeneration, wherein the data readers on the first module are wider in across-track direction than data readers on the supplemental module.

In another general embodiment, a magnetic head includes first modulesconfigured for writing and read verifying data on a tape in accordancewith a first generation and/or first format; and at least onesupplemental module coupled to the first modules, the at least onesupplemental module being configured for reading tape that was writtenby a head having modules configured for a different generation and/ordifferent format than the first generation and/or first format, whereinreaders of the supplemental modules additionally have at least one of alower tape-to-sensor spacing, larger reader width, and a greatershield-to-shield spacing than readers of the first modules.

In one general embodiment, a method includes detecting a format in whichdata on a tape is written; using a module configured for writing and/orreading data to and from the tape in a first format when the formatdetected is the first format; and using a supplemental module coupled tothe module for reading data from the tape in a second format when theformat detected is the second format, wherein the first format has ahigher data density than the second format.

In yet another general embodiment, a method includes receivingdesignation of at least a first format and/or first generation for tape;and acquiring a magnetic head having: a module configured for writingand/or reading data to and from a tape in the first format and/or firstgeneration; and a supplemental module coupled to the module, thesupplemental module being configured for reading a tape having datawritten in the first format and/or first generation, and/or a secondformat and/or a second generation. The magnetic head is then sent to anentity.

FIG. 1A illustrates a simplified tape drive 100 of a tape-based datastorage system, which may be employed in the context of the presentinvention. While one specific implementation of a tape drive is shown inFIG. 1A, it should be noted that the embodiments described herein may beimplemented in the context of any type of tape drive system.

As shown, a tape supply cartridge 120 and a take-up reel 121 areprovided to support a tape 122. One or more of the reels may form partof a removable cartridge and are not necessarily part of the system 100.The tape drive, such as that illustrated in FIG. 1A, may further includedrive motor(s) to drive the tape supply cartridge 120 and the take-upreel 121 to move the tape 122 over a tape head 126 of any type. Suchhead may include an array of readers, writers, or both.

Guides 125 guide the tape 122 across the tape head 126. Such tape head126 is in turn coupled to a controller 128 via a cable 130. Thecontroller 128, may be or include a processor and/or any logic forcontrolling any subsystem of the drive 100. For example, the controller128 typically controls head functions such as servo following, datawriting, data reading, etc. The controller 128 may operate under logicknown in the art, as well as any logic disclosed herein. The controller128 may be coupled to a memory 136 of any known type, which may storeinstructions executable by the controller 128. Moreover, the controller128 may be configured and/or programmable to perform or control some orall of the methodology presented herein. Thus, the controller may beconsidered configured to perform various operations by way of logicprogrammed into a chip; software, firmware, or other instructions beingavailable to a processor; etc. and combinations thereof.

The cable 130 may include read/write circuits to transmit data to thehead 126 to be recorded on the tape 122 and to receive data read by thehead 126 from the tape 122. An actuator 132 controls position of thehead 126 relative to the tape 122.

An interface 134 may also be provided for communication between the tapedrive 100 and a host (integral or external) to send and receive the dataand for controlling the operation of the tape drive 100 andcommunicating the status of the tape drive 100 to the host, all as willbe understood by those of skill in the art.

FIG. 1B illustrates an exemplary tape cartridge 150 according to oneembodiment. Such tape cartridge 150 may be used with a system such asthat shown in FIG. 1A. As shown, the tape cartridge 150 includes ahousing 152, a tape 122 in the housing 152, and a nonvolatile memory 156coupled to the housing 152. In some approaches, the nonvolatile memory156 may be embedded inside the housing 152, as shown in FIG. 1B. In moreapproaches, the nonvolatile memory 156 may be attached to the inside oroutside of the housing 152 without modification of the housing 152. Forexample, the nonvolatile memory may be embedded in a self-adhesive label154. In one preferred embodiment, the nonvolatile memory 156 may be aFlash memory device, ROM device, etc., embedded into or coupled to theinside or outside of the tape cartridge 150. The nonvolatile memory isaccessible by the tape drive and the tape operating software (the driversoftware), and/or other device.

By way of example, FIG. 2 illustrates a side view of a flat-lapped,bi-directional, two-module magnetic tape head 200 which may beimplemented in the context of the present invention. As shown, the headincludes a pair of bases 202, each equipped with a module 204, and fixedat a small angle α with respect to each other. The bases may be“U-beams” that are adhesively coupled together. Each module 204 includesa substrate 204A and a closure 204B with a thin film portion, commonlyreferred to as a “gap” in which the readers and/or writers 206 areformed. In use, a tape 208 is moved over the modules 204 along a media(tape) bearing surface 209 in the manner shown for reading and writingdata on the tape 208 using the readers and writers. The wrap angle θ ofthe tape 208 at edges going onto and exiting the flat media supportsurfaces 209 are usually between about 0.1 degree and about 5 degrees.

The substrates 204A are typically constructed of a wear resistantmaterial, such as a ceramic. The closures 204B made of the same orsimilar ceramic as the substrates 204A.

The readers and writers may be arranged in a piggyback or mergedconfiguration. An illustrative piggybacked configuration comprises a(magnetically inductive) writer transducer on top of (or below) a(magnetically shielded) reader transducer (e.g., a magnetoresistivereader, etc.), wherein the poles of the writer and the shields of thereader are generally separated. An illustrative merged configurationcomprises one reader shield in the same physical layer as one writerpole (hence, “merged”). The readers and writers may also be arranged inan interleaved configuration. Alternatively, each array of channels maybe readers or writers only. Any of these arrays may contain one or moreservo track readers for reading servo data on the medium.

FIG. 2A illustrates the tape bearing surface 209 of one of the modules204 taken from Line 2A of FIG. 2. A representative tape 208 is shown indashed lines. The module 204 is preferably long enough to be able tosupport the tape as the head steps between data bands.

In this example, the tape 208 includes 4 to 22 data bands, e.g., with 8data bands and 9 servo tracks 210, as shown in FIG. 2A on a one-halfinch wide tape 208. The data bands are defined between servo tracks 210.Each data band may include a number of data tracks, for example 1024data tracks (not shown). During read/write operations, the readersand/or writers 206 are positioned to specific track positions within oneof the data bands. Outer readers, sometimes called servo readers, readthe servo tracks 210. The servo signals are in turn used to keep thereaders and/or writers 206 aligned with a particular set of tracksduring the read/write operations.

FIG. 2B depicts a plurality of readers and/or writers 206 formed in agap 218 on the module 204 in Circle 2B of FIG. 2A. As shown, the arrayof readers and writers 206 includes, for example, 16 writers 214, 16readers 216 and two servo readers 212, though the number of elements mayvary. Illustrative embodiments include 8, 16, 32, 40, and 64 activereaders and/or writers 206 per array, and alternatively interleaveddesigns having odd numbers of reader or writers such as 17, 25, 33, etc.An illustrative embodiment includes 32 readers per array and/or 32writers per array, where the actual number of transducer elements couldbe greater, e.g., 33, 34, etc. This allows the tape to travel moreslowly, thereby reducing speed-induced tracking and mechanicaldifficulties and/or execute fewer “wraps” to fill or read the tape.While the readers and writers may be arranged in a piggybackconfiguration as shown in FIG. 2B, the readers 216 and writers 214 mayalso be arranged in an interleaved configuration. Alternatively, eacharray of readers and/or writers 206 may be readers or writers only, andthe arrays may contain one or more servo readers 212. As noted byconsidering FIGS. 2 and 2A-B together, each module 204 may include acomplementary set of readers and/or writers 206 for such things asbi-directional reading and writing, read-while-write capability,backward compatibility, etc.

FIG. 2C shows a partial tape bearing surface view of complimentarymodules of a magnetic tape head 200 according to one embodiment. In thisembodiment, each module has a plurality of read/write (R/W) pairs in apiggyback configuration formed on a common substrate 204A and anoptional electrically insulative layer 236. The writers, exemplified bythe write head 214 and the readers, exemplified by the read head 216,are aligned parallel to a direction of travel of a tape mediumthereacross to form an R/W pair, exemplified by the R/W pair 222.

Several R/W pairs 222 may be present, such as 8, 16, 32 pairs, etc. TheR/W pairs 222 as shown are linearly aligned in a direction generallyperpendicular to a direction of tape travel thereacross. However, thepairs may also be aligned diagonally, etc. Servo readers 212 arepositioned on the outside of the array of R/W pairs, the function ofwhich is well known.

Generally, the magnetic tape medium moves in either a forward or reversedirection as indicated by arrow 220. The magnetic tape medium and headassembly 200 operate in a transducing relationship in the mannerwell-known in the art. The piggybacked MR head assembly 200 includes twothin-film modules 224 and 226 of generally identical construction.

Modules 224 and 226 are joined together with a space present betweenclosures 204B thereof (partially shown) to form a single physical unitto provide read-while-write capability by activating the writer of theleading module and reader of the trailing module aligned with the writerof the leading module parallel to the direction of tape travel relativethereto. When a module 224, 226 of a piggyback head 200 is constructed,layers are formed in the gap 218 created above an electricallyconductive substrate 204A (partially shown). e.g., of AlTiC, ingenerally the following order for the R/W pairs 222: an insulating layer236, a first shield 232 typically of an iron alloy such as NiFe (—), CZTor Al—Fe—Si (Sendust), a sensor 234 for sensing a data track on amagnetic medium, a second shield 238 typically of a nickel-iron alloy(e.g., ˜80/20 at % NiFe, also known as permalloy), first and secondwriter pole tips 228, 230, and a coil (not shown). The sensor may be ofany known type, including those based on MR, GMIR, AMR, tunnelingmagnetoresistance (TMR), etc.

The first and second writer poles 228, 230 may be fabricated from highmagnetic moment materials such as ˜45/55 NiFe. Note that these materialsare provided by way of example only, and other materials may be used.Additional layers such as insulation between the shields and/or poletips and an insulation layer surrounding the sensor may be present.Illustrative materials for the insulation include alumina and otheroxides, insulative polymers, etc.

The configuration of the tape head 126 according to one embodimentincludes multiple modules, preferably three or more. In awrite-read-write (W-R-W) head, outer modules for writing flank one ormore inner modules for reading. Referring to FIG. 3, depicting a W-R-Wconfiguration, the outer modules 252, 256 each include one or morearrays of writers 260. The inner module 254 of FIG. 3 includes one ormore arrays of readers 258 in a similar configuration. Variations of amulti-module head include a R-W-R head (FIG. 4), a R-R-W head, a W-W-Rhead, etc. In yet other variations, one or more of the modules may haveread/write pairs of transducers. Moreover, more than three modules maybe present. In further approaches, two outer modules may flank two ormore inner modules, e.g., in a W-R-R-W, a R-W-W-R arrangement, etc. Forsimplicity, a W-R-W head is used primarily herein to exemplifyembodiments of the present invention. One skilled in the art apprisedwith the teachings herein will appreciate how permutations of thepresent invention would apply to configurations other than a W-R-Wconfiguration.

One embodiment of a magnetic head includes first modules (referred tobelow as first, second and/or third modules) configured for writingand/or reading data to and from a tape in a first format and/or firstgeneration and writing data, preferably with read-while-writeverification, to the tape in a second format and/or second generationthat is different than the first format and first generation. Asupplemental module is coupled to the first modules, the supplementalmodule being configured for reading a tape having data written in thesecond format and/or the second generation.

Another embodiment of a magnetic head includes first modules configuredfor writing and read verifying data on a tape in accordance with a firstgeneration and/or first format. At least one supplemental module iscoupled to the first modules, the at least one supplemental module beingconfigured for reading tape that was written, and preferably readverified, by a head having modules configured for a different generation(e.g. different track or linear densities) and/or different format(e.g., 4, 8, 16, etc. data bands) than the first generation and/or firstformat, where readers of the supplemental modules additionally have atleast one of a lower average tape-to-sensor spacing (also known ashead-to-media spacing or the like) in use than readers of the firstmodules, larger average data reader widths in the cross track directionthan data readers of the first modules, and/or a greatershield-to-shield spacing than readers of the first modules. Theseparameters allow the readers on the supplemental module to read backdata on the older generation tape with lower error rates than thereaders on the modules.

FIG. 5 illustrates a magnetic head 126 according to one embodiment ofthe present invention that includes first, second and third modules 302,304, 306 each having a tape bearing surface 308, 310, 312 respectively,which may be flat, contoured, etc. (as in any of the embodimentsdescribed herein). The modules 302, 304, 306 may be configured forwriting and/or reading data to and from a tape in a first format and/orfirst generation. Note that while the term “tape bearing surface”appears to imply that the surface facing the tape 315 is in physicalcontact with the tape bearing surface, this is not necessarily the case.Rather, only a portion of the tape may be in contact with the tapebearing surface, constantly or intermittently, with other portions ofthe tape riding (or “flying”) above the tape bearing surface on a layerof air, sometimes referred to as an “air bearing”. The first module 302will be referred to as the “leading” module as it is the first moduleencountered by the tape in a three module design for tape moving in theindicated direction. The third module 306 will be referred to as the“trailing” module. The trailing module follows the middle module and isthe last module seen by the tape in a three module design. The leadingand trailing modules 302, 306 are referred to collectively as outermodules. Also note that the outer modules 302, 306 will alternate asleading modules, depending on the direction of travel of the tape 315.

In one embodiment, the tape bearing surfaces 308, 310, 312 of the first,second and third modules 302, 304, 306 lie on about parallel planes(which is meant to include parallel and nearly parallel planes, e.g.,between parallel and tangential as in FIG. 6), and the tape bearingsurface 310 of the second module 304 is above the tape bearing surfaces308, 312 of the first and third modules 302, 306. As described below,this has the effect of creating the desired wrap angle α₂ of the taperelative to the tape bearing surface 310 of the second module 304.

Where the tape bearing surfaces 308, 310, 312 lie along parallel ornearly parallel yet offset planes, intuitively, the tape should peel offof the tape bearing surface 308 of the leading module 302. However, thevacuum created by the skiving edge 318 of the leading module 302 hasbeen found by experimentation to be sufficient to keep the tape adheredto the tape bearing surface 308 of the leading module 302. The trailingedge 320 of the leading module 302 (the end from which the tape leavesthe leading module 302) is the approximate reference point which definesthe wrap angle α₂ over the tape bearing surface 310 of the second module304. The tape stays in close proximity to the tape bearing surface untilclose to the trailing edge 320 of the leading module 302. Accordingly,read and/or write elements 322 may be located near the trailing edges ofthe outer modules 302, 306. These embodiments are particularly adaptedfor write-read-write applications.

A benefit of this and other embodiments described herein is that,because the outer modules 302, 306 are fixed at a determined offset fromthe second module 304, the inner wrap angle α₂ is fixed when the modules302, 304, 306 are coupled together or are otherwise fixed into a head.The inner wrap angle α₂ is approximately tan⁻¹(δ/W) where δ is theheight difference between the planes of the tape bearing surfaces 308,310 and W is the width between the opposing ends of the tape bearingsurfaces 308, 310. An illustrative inner wrap angle α₂ is in a range ofabout 0.5° to about 1.1°, though can be any angle required by thedesign.

Beneficially, the inner wrap angle α₂ on the side of the module 304receiving the tape (leading edge) will be larger than the inner wrapangle α₃ on the trailing edge, as the tape 315 rides above the trailingmodule 306. This difference is generally beneficial as a smaller α₃tends to oppose what has heretofore been a steeper exiting effectivewrap angle.

Note that the tape bearing surfaces 308, 312 of the outer modules 302,306 are positioned to achieve a negative wrap angle at the trailing edge320 of the leading module 302. This is generally beneficial in helpingto reduce friction due to contact with the trailing edge 320, providedthat proper consideration is given to the location of the crowbar regionthat forms in the tape where it peels off the head. This negative wrapangle also reduces flutter and scrubbing damage to the elements on theleading module 302. Further, at the trailing module 306, the tape 315flies over the tape bearing surface 312 so there is virtually no wear onthe elements when tape is moving in this direction. Particularly, thetape 315 entrains air and so will not significantly ride on the tapebearing surface 312 of the third module 306 (some contact may occur).This is permissible, because the leading module 302 is writing while thetrailing module 306 is idle.

Writing and reading functions are performed by different modules at anygiven time. In one embodiment, the second module 304 includes aplurality of data and optional servo readers 331 and no writers. Thefirst and third modules 302, 306 include a plurality of writers 322 andno readers, with the exception that the outer modules 302, 306 mayinclude optional servo readers. The servo readers may be used toposition the head during reading and/or writing operations. The servoreader(s) on each module are typically located towards the end of thearray of readers or writers.

By having only readers or side by side writers and servo readers in thegap between the substrate and closure, the gap length can besubstantially reduced. Typical heads have piggybacked readers andwriters, where the writer is formed above each reader. A typical gap is25-35 microns. However, irregularities on the tape may tend to droopinto the gap and create gap erosion. Thus, the smaller the gap is thebetter. The smaller gap enabled herein exhibits fewer wear relatedproblems.

In some embodiments, the second module 304 has a closure, while thefirst and third modules 302, 306 do not have a closure. Where there isno closure, preferably a hard coating is added to the module. Onepreferred coating is diamond-like carbon (DLC).

In the embodiment shown in FIG. 5, the first, second, and third modules302, 304, 306 each have a closure 332, 334, 336, which extends the tapebearing surface of the associated module, thereby effectivelypositioning the read/write elements away from the edge of the tapebearing surface. The closure 332 on the second module 304 can be aceramic closure of a type typically found on tape heads. The closures334, 336 of the first and third modules 302, 306, however, may beshorter than the closure 332 of the second module 304 as measuredparallel to a direction of tape travel over the respective module. Thisenables positioning the modules closer together. One way to produceshorter closures 334, 336 is to lap the standard ceramic closures of thesecond module 304 an additional amount. Another way is to plate ordeposit thin film closures above the elements during thin filmprocessing. For example, a thin film closure of a hard material such asSendust or nickel-iron alloy (e.g., 45/55) can be formed on the module.

With reduced-thickness ceramic or thin film closures 334, 336 or noclosures on the outer modules 302, 306, the write-to-read gap spacingcan be reduced to less than about 1 mm, e.g., about 0.75 mm, or 50% lessthan standard LTO tape head spacing. The open space between the modules302, 304, 306 can still be set to approximately 0.5 to 0.6 mm, which insome embodiments is ideal for stabilizing tape motion over the secondmodule 304.

The magnetic head 126 of FIG. 5 also includes a supplemental module 324,as will be explained in further detail below. In the example shown, thesupplemental module 324 has an at least partially beveled tape bearingsurface, as also described below. Moreover, the supplemental module 324may be configured for reading a tape having data written in the secondformat and/or the second generation.

Depending on tape tension and stiffness, it may be desirable to anglethe tape bearing surfaces of the outer modules relative to the tapebearing surface of the second module. FIG. 6 illustrates an embodimentwhere the modules 302, 304, 306, are in a tangent or nearly tangent(angled) configuration. Particularly, the tape bearing surfaces of theouter modules 302, 306 are about parallel to the tape at the desiredwrap angle α₂ of the second module 304. In other words, the planes ofthe tape bearing surfaces 308, 312 of the outer modules 302, 306 areoriented at about the desired wrap angle α₂ of the tape 315 relative tothe second module 304. The tape will also pop off of the trailing module306 in this embodiment, thereby reducing wear on the elements in thetrailing module 306. These embodiments are particularly useful forwrite-read-write applications. Additional aspects of these embodimentsare similar to those given above.

The embodiment 126 of FIG. 6 also includes multiple supplementalmodules, including a first supplemental module 324 and a secondsupplemental module 325. As shown, the second supplemental module 325 isshown with an at least partially beveled tape bearing surface, while thefirst supplemental module 324 is shown with a planar tape bearing face.The first supplemental module 324 may be oriented in a tangent or nearlytangent (angled) configuration as shown, or may be overwrapped as inFIG. 7.

The second supplemental module 325 may be configured for reading a tapehaving data written in the first format and/or first generation, and/ora third format and/or third generation that is different than the firstand second formats and the first and second generations. The secondsupplemental module 325, in another approach, is configured for readinga tape having data written in a second format having a lower datadensity than the first format. According to various approaches, thesecond supplemental module 325 may include any of the approachesdescribed and/or suggested herein.

Typically, the tape wrap angles may be set about midway between theembodiments shown in FIGS. 5 and 6.

FIG. 7 illustrates an embodiment where the modules 302, 304, 306 are inan overwrap configuration. Particularly, the tape bearing surfaces 308,312 of the outer modules 302, 306 are angled slightly more than the tape315 wrap angle α₂ relative to the second module 304. In this embodiment,the tape does not pop off of the trailing module, allowing it to be usedfor writing or reading. Accordingly, the leading and middle modules canboth perform reading and/or writing functions while the trailing modulecan read any just-written data. Thus, these embodiments are preferredfor write-read-write, read-write-read, and write-write-readapplications. In the latter embodiments, closures should be wider thanthe tape canopies for ensuring read capability. The wider closures mayrequire a wider gap-to-gap separation. Therefore a preferred embodimenthas a write-read-write configuration, which may use shortened closuresthat thus allow closer gap-to-gap separation. A supplemental module 324is also present.

Additional aspects of the embodiments shown in FIGS. 6 and 7 are similarto those given above.

A 32 channel version of a multi-module head 126 may use cables 350having leads on the same or smaller pitch as current 16 channelpiggyback LTO modules, or alternatively the connections on the modulemay be organ-keyboarded for a 50% reduction in cable span. Over-under,writing pair unshielded cables may be used for the writers, which mayhave integrated servo readers.

The outer wrap angles α₁ may be set in the drive, such as by guides ofany type known in the art, such as adjustable rollers, slides, etc. Forexample, rollers having an offset axis may be used to set the wrapangles. The offset axis creates an orbital are of rotation, allowingprecise alignment of the wrap angle α₁.

To assemble any of the embodiments described above, conventional u-beamassembly can be used. Accordingly, the mass of the resultant head may bemaintained or even reduced relative to heads of previous formats,including previous generations. In other approaches, the modules may beconstructed as a unitary body. Those skilled in the art, armed with thepresent teachings, will appreciate that other known methods ofmanufacturing such heads may be adapted for use in constructing suchheads.

When upgrading to a newer tape product format, such as a latergeneration, backward read compatibility is desirable for a magnetichead, e.g., the ability to read data on tapes having earlier formats.However, read elements in the newer format drives are generally narrowerthan the readers in the older format drives, e.g., to enable reducedtrack width and thus higher data capacity on tape. This may result inpoorer error rates when reading older format media in the new drive, asthe narrower new format read elements have poorer broadbandsignal-to-noise characteristics and are more sensitive to signal lossdue to media defects.

As a result, conventional products must either abandon backwardcompatibility, or alternatively add more read elements to the existinghead modules, or alternatively limit areal density of the new format toenable some level of backward compatibility. However, by abandoningbackward compatibility, conventional products are unable to access datawritten to tape in earlier formats. Moreover, by adding more readelements to the existing head modules increases the I/O on each module,thus making cabling more difficult in terms of size and flexibility.

Embodiments described and/or suggested herein preferably provide a headwith readers that read a first format such as a newer format or oneassociated with a particular platform, as well as having additionalbackward and/or alternate-platform compatible readers, e.g., to readdata on tapes having earlier/other formats and/or written on anotherplatform that is incompatible with the first format. Moreover, this isideally accomplished in a manner that does not compromise the headdesign for the first format.

According to exemplary embodiments, which are in no way intended tolimit the invention, a magnetic head may include modules configured forwriting and/or reading data to and from a tape in a first format. Suchmodules may include an array of readers, writers, or both, according tothe first format, which may include any desirable configurationdescribed herein. According to various approaches, the first format maybe a later generation format (e.g., than a second format), a formatassociated with a particular standard or platform, a preferred format,etc.

Moreover, the magnetic head may also include a supplemental modulecoupled to the modules (see, e.g., 302, 304, 306, 324 and 325 of FIGS.5-7). The supplemental module is preferably configured for reading atape having data written in a second format, but is not limited thereto.Accordingly, the supplemental module may also include an array ofreaders, according to the second format, which is preferably a differentconfiguration than that of the modules, as will soon become apparent.

The first format may have a higher data density than the second formatin terms of average linear and/or average areal data density on tape,which can be measured, e.g., in bits per inch, bits per square inch,etc. Thus in one approach, it may be desirable that the widths ofreaders on the modules in a cross-track direction are narrower thanwidths of readers on the supplemental module. As a result, the narrowerwidths of the readers on the modules allow the modules to read data of ahigher density than the readers on the supplemental module.

However, the wider widths of the readers on the supplemental moduleenables reduced signal to noise ratio (SNR) and improved error rates,etc. when reading data in an earlier format, e.g., which may have widerdata tracks. Conversely, the larger widths of the readers on thesupplemental module may also be wider than the actual data tracks of agiven (e.g., newer) format, written to a tape. This may cause thereaders on the supplemental module to cross over adjacent data tracks,thereby degrading SNR, read errors, etc.

As a result, in some approaches, the supplemental module may beincapable of reading data in the first format (e.g., a newer format),and/or incapable of reading data written and read verified by themodules. According to an example, which is in no way intended to limitthe invention, the supplemental module may be able to read 8 data tracksper pass, while the first format may be written in 16 data tracks perpass. As a result, the 8 channels of the supplemental module may notalign with the 16 data tracks, e.g., because of spacing between the datatracks, the size of the readers, the size of the data tracks, etc.Therefore, the supplemental module would not be able to read the data inthe first format.

However, in yet another approach, widths of data readers on one or moreof the modules in a cross-track direction may be wider than widths ofreaders on the supplemental module. Referring back to the examplespresented directly above, the narrower widths of the readers on thesupplemental module may allow for greater flexibility for readback,e.g., if the tape is distorted, environmental conditions have changed,etc., while also maintaining backward compatibility. In anotherapproach, the narrower reader widths of the supplemental module allow ahead to be usable with one format such as an older format, and also ableto read a tape written in a newer format, such as a later generation.This also allows the data readers on the first modules to be moresensitive during read-while-write verification of the wider trackswritten by the writers in the second format and/or generation, as wellas allows them to read and/or write earlier generations and/or formats.When the tracks are shingled, the wider data readers of the firstmodule(s) may be too wide to go back and effectively read the shingledtracks, and so the narrower data readers of the supplemental module maybe used to readback of data on a tape written by the first modules inthe second format and/or generation.

Accordingly, in one embodiment, the drive controller may be configuredto write data in shingled tracks, where the data readers of the one ormore of the first modules are wider than 50% of an average track widthof the shingled tracks. In some approaches the data readers of the firstmodules may be wider than 50%, 75%, 90%, 100%, 125%, 150%, or more ofthe average track width of the shingled tracks.

In another approach, the supplemental module may include readers forreading the second format and a third format. While the third format mayhave a lower data density than the first format, according to differentapproaches, the third format may have a data density that is higher orlower than the second format. As described above, data density may bemeasured in terms of average linear and/or average bit density on tape,which can be measured, e.g., in bits per inch, bits per square inch,etc. Thus, according to a further approach, the number of readers on thesupplemental module and/or their widths in a cross-track direction maybe compatible with a second format and a third format. In differentapproaches, the supplemental module may be compatible with at least twoformats (e.g., second and third format), at least four formats, multipleformats, etc., which may be older formats than a first format, asexplained above. According to one approach, incorporating a secondsupplemental module may increase the number of formats a given magnetichead is compatible with, e.g., as shown illustratively in FIG. 6 and asexplained in detail below.

In one approach, the readers for reading the second format and the thirdformat may be arranged in two spatially separated arrays on thesupplemental module, e.g. one above the other, aligned along a commonlongitudinal axis, etc. In another approach, the readers for readingmore than one format, e.g., the second format and the third format, maybe interleaved on the supplemental module e.g. as two interleavedarrays. According to an illustrative example, which is in no wayintended to limit the invention, a 32 channel head may have backwardcompatibility to 16 channel formatted tapes. In this case, alternatingreaders of the 32 channel formatted head may have alternating widths.Thus, the 32 channel formatted head may be able to read data of a secondformat, e.g., 32 data tracks with a given average width and spacingtherebetween, while also being able to read data written in a thirdformat, e.g., 16 data tracks with a different average width and spacingtherebetween.

In one illustrative embodiment, the supplemental module may be builtwith 32 channels and 4 servo readers. Depending on the application, twoof the servo readers may be used when reading data in a 32 channelformat, while the other two servo readers may be used when reading datain a 16 channel format, but is not limited thereto. Additionally, theservo readers and/or data readers on the supplemental module may be usedfor band detection and/or skew control for one or more of the dataformats.

In one approach, the supplemental module may have an at least partiallybeveled tape bearing surface that is truly beveled, partially rounded,and/or otherwise not flat across the entire tape-facing surface, e.g.,as shown in FIGS. 5 and 6). Having an at least partially beveled tapebearing surface on the supplemental module may be desirable depending onthe embodiment, as it may reduce the friction between the tape and thetape bearing surface of the supplemental module.

In another approach, the supplemental module may set a tape wrap anglerelative to one of the modules positioned immediately adjacent thereto.The supplemental module may set a tape wrap angle e.g., by itspositioning relative to the nearest module. An illustrative wrap anglerange is less than about 3°, preferably less than about 2°.

In one approach, the supplemental module may be oriented in a tangent orslightly overwrapped orientation relative to the direction of tapetravel, thereby enabling bi-directional operation. See, e.g., FIG. 6.

In another approach, the supplemental module may be positioned so that atape wraps both tape-engaging edges of the supplemental module, therebyalso enabling bi-directional operation. Thus, according to one approach,the supplemental module may read data from the tape in both directionsof tape travel. See, e.g., FIG. 7.

In another approach, the magnetic head may include a second supplementalmodule coupled to the modules and/or the supplemental module. In oneapproach, the supplemental module may be positioned on an opposite sideof the modules than the second supplemental module in a tape traveldirection, e.g., as shown in FIG. 6. However, in other approaches, thesupplemental module may be coupled to the modules on the same side ofthe modules as the second supplemental module, coupled to the secondsupplemental module itself, etc., or any other desirable position.

The second supplemental module may preferably be configured for readinga tape having data written in a third format, such as one having a lowerdata density than the second format and/or from a different platform.However, in still another approach, the supplemental module and thesecond supplemental module may be configured for reading data written inthe same format, e.g., for bi-directional read operation. According tovarious approaches, the second supplemental module may be positionedaccording to any of the approaches described above for the supplementalmodule. Moreover, the supplemental module and the second supplementalmodule may have the same or different positioning relative to themodules and/or tape path, depending on the desired embodiment.

According to another exemplary embodiment, a data storage system mayinclude a magnetic head having modules configured for writing and/orreading data to and from a tape in a first format (see 302, 304 and 306of FIGS. 5-7, and 804 and 806 of FIG. 8). According to variousapproaches, the modules may include any modules described and/orsuggested herein.

The data storage system may also include a supplemental module coupledto the modules (see 324, 325 of FIGS. 5-7 and 802 of FIG. 8), thesupplemental module being configured for reading a tape having datawritten in the first format. However, it may be preferable that thesupplemental module is not used for reading unless one of the modulesfor reading data becomes at least partially inoperative, e.g., unable toreliably reproduce data because one of the readers has failed orotherwise rendered at least partially inoperative, etc. Thus, thesupplemental module may be used as a back-up so that the magnetic headmay still be used in read-only mode. In one approach, when the at leastone of the modules becomes at least partially inoperative, a signal maybe sent to a user administrator which may notify a user. In anotherapproach, when the at least one of the modules becomes at leastpartially inoperative, the supplemental module may be employed by usinge.g., computer program code, logic, etc., which may be stored in asystem manager, controller, user interface, etc.

The supplemental module is preferably characterized by fabricationseparately from the modules, and thus has physical characteristics ofsuch separate fabrication such as marks from dicing, different thin filmconstruction than the modules, etc. The supplemental module may bepermanently coupled to one or more of the modules, or a support thereof,e.g., via an adhesive, sonic welding, fasteners, clips, etc.

Although three modules 302, 304, 306 are illustrated in combination withthe supplemental module(s) 324, 325 in FIGS. 5-7, in other approaches, amagnetic head may include any number of modules e.g., at least one, two,at least two, at least three, a plurality, etc. depending on the desiredembodiment. Moreover, the modules may be positioned with any orientationrelative to each other and/or the supplemental modules of the magnetichead, depending on the desired embodiment.

FIG. 8 depicts a magnetic head 800, in accordance with one embodiment.As an option, the present magnetic head 800 may be implemented inconjunction with features from any other embodiment listed herein, suchas those described with reference to the other Figures. Of course,however, such magnetic head 800 and others presented herein may be usedin various applications and/or in permutations which may or may not bespecifically described in the illustrative embodiments listed herein.Further, the magnetic head 800 presented herein may be used in anydesired environment.

As illustrated in FIG. 8, the magnetic head 800 includes a supplementalmodule 802 coupled to the modules 804, 806, over which a magnetic tape808 may run. According to various approaches, the magnetic head 800,supplemental module 802 and/or the modules 804, 806 may include any ofthe approaches described and/or suggested herein, depending on thedesired embodiment. Thus, although not illustrated, the magnetic head800 may include a second supplemental module coupled to the modules 804,806 and/or supplemental module 802 according to any of the approachesdescribed and/or suggested herein, depending on the desired embodiment.

According to various embodiments, a data storage system may include amagnetic head having modules configured for writing and/or reading datato and from a tape in a first format (see e.g., 302, 304 and 306 ofFIGS. 5-7, and 804 and 806 of FIG. 8). According to various approaches,the modules may include any modules described and/or suggested herein.The data storage system may also include one or more supplementalmodules (see, e.g., 324 of FIGS. 5-7 and 802 of FIG. 8) of any type,configuration, position, etc. as described or suggested herein, in anycombination. Thus, for example, the embodiment shown in FIG. 6 mayinstead have one or two supplemental modules configured in an overwrapconfiguration, and thus FIG. 6 (and the other Figures) should be deemedto include any and all possible permutations.

FIG. 9 depicts a method 900, in accordance with one embodiment. As anoption, the present method 900 may be implemented in conjunction withfeatures from any other embodiment listed herein, such as thosedescribed with reference to the other Figures. Of course, however, suchmethod 900 and others presented herein may be used in variousapplications and/or in permutations which may or may not be specificallydescribed in the illustrative embodiments listed herein. Further, themethod 900 presented herein may be used in any desired environment.

The method 900 includes detecting a format in which data on a tape iswritten. See operation 902. According to various approaches, the formatmay be detected by reading the format from cartridge memory, by readingheaders on the tape, by reading a portion of the data, by receiving aninstruction from another machine such as a library controller, etc.

With continued reference to FIG. 9, operation 904 of method 900 includesusing one or more modules configured for writing and/or reading data toand from the tape in a first format when the format detected is thefirst format. As described above, the first format may be an earlier orlater generation format (e.g., than the second format), a formatassociated with a particular standard or platform, a preferred format,etc.

Method 900 additionally includes using a supplemental module coupled tothe module(s) for reading data from the tape in a second format when theformat detected is the second format, where, for example, the firstformat has a higher data density than the second format, e.g., forbackward compatibility. See operation 906. In an alternate embodiment,the supplemental module may be used for reading a newer format, asdescribed by way of example below. Again, as described above, the datadensity may be in terms of average linear and/or average areal datadensity on tape, which can be measured, e.g., in bits per inch, bits persquare inch, etc.

According to various approaches, the supplemental module may be usedimmediately when the second format is detected, after a period of timeonce the second format is detected, etc. With continued reference to thepresent description, the supplemental module may be “used” by turning onthe readers within the supplemental module, but is not limited thereto.Moreover, once the supplemental module has been employed, the readers inthe modules corresponding to the first format may be turned off, set toan idle state, etc., according to different approaches.

In one embodiment, the second format may be the same as the firstformat. In an approach where the widths of the readers used to readverify tracks being written in a shingled writing mode are too wide toread the shingled tracks, e.g., in the first format, the readers of thesupplemental module may be narrow enough to read the shingled tracks.Thus, the supplemental module may be used as the primary reader forreadback of the shingled tracks in the first format. While the widerreaders that were used to read-verify the first format cannot read theshingled tracks, they may be usable to read and/or write tape in anearlier format, e.g., the second format. This approach iscounterintuitive, but is very useful in enabling both narrow shingledtrack widths while also enabling backward read and write compatibility.Thus, an embodiment may include features similar to those of FIG. 9 inconjunction with the precepts of this paragraph.

With reference now to FIG. 10, a method 1000, is depicted in accordancewith one embodiment. As an option, the present method 1000 may beimplemented in conjunction with features from any other embodimentlisted herein, such as those described with reference to the otherFigures. Of course, however, such method 1000 and others presentedherein may be used in various applications and/or in permutations whichmay or may not be specifically described in the illustrative embodimentslisted herein. Further, the method 1000 presented herein may be used inany desired environment.

Operation 1002 of method 1000 includes receiving designation of a firstformat and a second format for tape. In a preferred approach, the firstformat has a higher data density than the second format in terms ofaverage linear and/or average areal data density on tape, which can bemeasured, e.g., in bits per inch, bits per square inch, etc.

In one approach, the designation of the first and/or second formats maybe received from a user, but is not limited thereto. In otherapproaches, the designation of the first and/or second formats may bereceived from computer program code, logic, a lookup table, etc.

With continued reference to FIG. 10, method 1000 includes acquiring amagnetic head having: one or more modules configured for writing and/orreading data to and from a tape in the first format and/or firstgeneration; and a supplemental module coupled to the module(s), thesupplemental module being configured for reading a tape having datawritten in the first format and/or first generation, and/or a secondformat and/or a second generation. See operation 1004.

Additionally, operation 1006 of method 1000 includes sending themagnetic head to an entity such as a user, company, etc. However,according to an alternative approach, the method 1000 may includecoupling the head to a magnetic storage system, wherein the magneticstorage system is sent to the user.

Moreover, a magnetic head having one or more supplemental modules may betailored for a particular user, client, system, etc., depending on thedesired embodiment. Each data format may have a respective supplementalmodule, which would preferably offer reader compatibility to any earlierand/or other format. According to an exemplary embodiment, which is inno way intended to limit the invention, a user operating on an earlierformat who wishes to upgrade to the latest format would implement a headcompatible with the latest format and a supplemental module compatiblewith the earlier format. Thus, the user's system may be upgraded to thelatest format, while maintaining the ability to read the data previouslyrecorded using the earlier format. Moreover, according to one approach,the latest formatted head may have read compatibility back to an everearlier format. In another approach, formats may be grouped together,e.g., so as to use a common supplemental module. For example, which isin no way intended to limit the invention, both Linear Tape Open (LTO)1and LTO2 formatted customers may be able to use a LTO2 formattedsupplemental module. Similarly, both LTO3 and LTO4 formatted customersmay be able to use a LTO4 formatted supplemental module. This may bedesirable as it may simplify part numbers and format configurations.

Moreover, any increase in mass of the overall magnetic head caused bythe inclusion of the at least one supplemental module may be offset bytrimming the supports, e.g., U-beams of the modules and/or by usinglower density material e.g., for the U-beams.

It will be clear that the various features of the foregoing systemsand/or methodologies may be combined in any way, creating a plurality ofcombinations from the descriptions presented above.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as “logic,” a “circuit,” “module,” or“system.” Furthermore, aspects of the present invention may take theform of a computer program product embodied in one or more computerreadable medium(s) having computer readable program code embodiedthereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a non-transitory computer readable storage medium. A computerreadable storage medium may be, for example, but not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, or device, or any suitable combinationof the foregoing. More specific examples (a non-exhaustive list) of thenon-transitory computer readable storage medium include the following: aportable computer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a portable compact disc read-only memory (e.g.,CD-ROM), a Blu-ray disc read-only memory (BD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a non-transitory computerreadable storage medium may be any tangible medium that is capable ofcontaining, or storing a program or application for use by or inconnection with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a non-transitory computer readable storage medium and that cancommunicate, propagate, or transport a program for use by or inconnection with an instruction execution system, apparatus, or device,such as an electrical connection having one or more wires, an opticalfibre, etc.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fibre cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer, for example through the Internet using an Internet ServiceProvider (ISP).

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart(s) and/orblock diagram block or blocks.

It will be further appreciated that embodiments of the present inventionmay be provided in the form of a service deployed on behalf of acustomer.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of an embodiment of the presentinvention should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the followingclaims and their equivalents.

What is claimed is:
 1. An apparatus, comprising: at least one firstmodule configured for writing and/or reading data to and from a magneticmedium in a first format and/or first generation and writing data to themagnetic medium in a second format and/or second generation that isdifferent than the first format and first generation; and a supplementalmodule coupled to the first module, the supplemental module beingconfigured for reading a magnetic medium having data written in thesecond format and/or the second generation.
 2. An apparatus as recitedin claim 1, wherein the magnetic medium is a tape, wherein thesupplemental module sets a tape wrap angle relative to one of themodules positioned immediately adjacent thereto.
 3. An apparatus asrecited in claim 1, wherein the magnetic medium is a tape, wherein thesupplemental module is positioned so that a tape wraps both edges of thesupplemental module.
 4. An apparatus as recited in claim 1, wherein thesupplemental module is configured to read data from the magnetic mediumin two directions of media travel.
 5. An apparatus as recited in claim1, wherein the supplemental module is not used for reading unless thefirst module for reading data becomes inoperative.
 6. An apparatus ad asrecited in claim 1, wherein the data readers on the first module arewider in a cross-track direction than data readers on the supplementalmodule.
 7. An apparatus as recited in claim 1, further comprising asecond supplemental module coupled to the first and supplementalmodules, the second supplemental module being configured for reading amagnetic medium having data written in the first format and/or firstgeneration, and/or a third format and/or third generation that isdifferent than the first and second formats and the first and secondgenerations.
 8. An apparatus as recited in claim 1, further comprising:a drive mechanism for passing a magnetic medium over the modules; and acontroller electrically coupled to the magnetic head.
 9. An apparatus asrecited in claim 8, wherein the controller is configured to write thedata in shingled tracks, wherein the data readers of the one or more ofthe first modules are wider than 50% of an average track width of theshingled tracks.
 10. An apparatus as recited in claim 8, wherein thecontroller is configured to: detect a format in which data on a magneticmedium is written; use a module configured for writing and/or readingdata to and from the magnetic medium in a first format when the formatdetected is the first format; and use a supplemental module coupled tothe module for reading data from the magnetic medium in a second formatwhen the format detected is the second format.
 11. A method, comprising:detecting a format in which data on a magnetic medium is written; usinga module configured for writing and/or reading data to and from themagnetic medium in a first format when the format detected is the firstformat; and using a supplemental module coupled to the module forreading data from the magnetic medium in a second format when the formatdetected is the second format.
 12. A method as recited in claim 11,wherein widths of data readers on the first modules in a cross-trackdirection are wider than widths of readers on the at least onesupplemental module.
 13. A method as recited in claim 11, wherein thefirst format has a higher data density than the second format.
 14. Amethod as recited in claim 11, wherein the magnetic medium is a tape,wherein the supplemental module sets a tape wrap angle relative to oneof the modules positioned immediately adjacent thereto.
 15. A method asrecited in claim 11, wherein the magnetic medium is a tape, wherein thesupplemental module is positioned so that a tape wraps both edges of thesupplemental module.
 16. A method as recited in claim 11, wherein thesupplemental module is configured to read data from the magnetic mediumin two directions of media travel.
 17. A method as recited in claim 11,wherein the supplemental module is not used for reading unless the firstmodule for reading data becomes inoperative.